iris: Implement ARB_indirect_parameters

iris: Implement ARB_indirect_parameters

iris_draw_vbo is divided into two functions to remove unnecessary
operations from the loop. This implementation of ARB_indirect_parameters
takes into account NV_conditional_render by saving MI_PREDICATE_RESULT
at the start of a draw call and restoring it at the end also the result
of NV_conditional_render is taken into account when computing predicates
that limit draw calls for ARB_indirect_parameters in a similar way
to 1952fd8d in ANV.

v2: Optimize indirect draws (suggested by Kenneth Graunke)
v3: (by Kenneth Graunke)
 - Fix an issue where indirect draws wouldn't set patch information
   before updating the compiled TCS.
 - Move some code back to iris_draw_vbo to avoid duplicating it.
 - Fix minor indentation issues.

Signed-off-by: Illia Iorin <illia.iorin@globallogic.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>